Specific impairment of hand laterality recognition in mastectomy patients

It is common for mastectomy patients to present with sensorimotor symptoms that can affect the execution of voluntary movements, which engages endogenous motor representations. It is therefore necessary to expand our knowledge of motor representations in mastectomy patients to propose novel and complementary tools to conventional rehabilitation. The investigation of such motor representations may be conducted through the utilisation of tasks that implicitly engage a motor imagery process. Accordingly, the aim of our study was to ascertain the impact of a unilateral mastectomy on motor representations, employing an implicit motor imagery task. To investigate this, seven mastectomy participants and ten matched healthy controls had to judge the laterality of hands presented in a different view (i.e., back and palm) and different orientations (i.e., 0°, 90° lateral, 90° medial and 180°). The results demonstrated that the mastectomy group exhibited a lower hit rate than the control participants and a longer response time, particularly for the palm view in postures that engaged significant biomechanical constraints (i.e., 90° lateral and 180°). These findings suggest that mastectomy procedure induce alterations in patients’ motor representations. Accordingly, we propose that the mastectomy participants had greater difficulty in simulating the movement that allowed them to rotate their own hand in order to align it with the hand image presented on the computer screen.